linux-kernel - Re: [PATCH 0/12] ACPI: Rework the handling of power resources

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Message-ID: <16771896.0qvD1a7278@vostro.rjw.lan>
Date:	Fri, 11 Jan 2013 22:57:33 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/12] ACPI: Rework the handling of power resources

On Friday, January 04, 2013 12:16:48 AM Rafael J. Wysocki wrote:
> Hi All,
> 
> There are some problems with our handling of ACPI power resources that have
> accumulated over time or have never been addressed.
> 
> First of all, the interface represented by
> acpi_power_resource_[un]register_device() doesn't really work as it should,
> so it needs to be redesigned (details in the changelog of patch [1/12]).
> 
> Second, power resources really have to be treated in a special way by the
> ACPI namespace scanning code, because they may need to be ready to use as
> soon as they are discovered.  Moreover, the are represented by struct
> acpi_device objects, so that they appear in sysfs along with "regular" ACPI
> device nodes, they really don't represent devices, so they need special
> configuration treatment in some cases.  This special casing is obnoxiously
> present in scan.c, but if we accept the fact that power resources really are
> a special case, things can be simplified quite a bit (patch [3/12] with some
> preparations in [2/12]).
> 
> If the above changes are made, then it turns out that the entire
> acpi_power_driver structure is not necessary any more and we don't need the
> device power states of power resources for anything (patches [4-5/12]).
> 
> Moreover, ACPI power resources are supposed to be ordered.  Namely, they have
> an attribute defining the order in which they are supposed to turned on and
> off.  Currently, though, we don't take that attribute into accound, although
> we obviously should do that.  After the previous changes that may be
> implemented at a relatively low cost (patch [6-7/12]).
> 
> Patches [8-9/12] move code around and clean it up in preparation for patch
> [10/12], which consolidates the way in which power resources lists are
> extracted from the output of _PRW and _PR[0-3].
> 
> Patch [11/12] improves the handling of power resource initialization errors
> and patch [12/12] causes the system level attribute of wakeup power resources
> to be taken into account during device setup.
> 
> All patches are on top of the git branch at:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
> 
> Tested on HP nx6325 (and other boxes where ACPI power resources aren't used).

There has been a week without a single comment, so I gather the thing is
not controversial at all.  I'll put it into linux-next for v3.9, then.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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